What is the coldest you’ll wear an automatic watch?

I've worn my Omega GMT in -40c, no problem what so ever

I've never thought about what watch I'm wearing, but I never have to brave more than -10°C (+14°F in old money) so it's not that much of a stretch.

For those of us using real units:

40°F = 4.44°C

30°F = -1.11°C

20°F = -6.67°C

10°F = -12.22°C

I have worn my SKX when it was -20 without any problem and that is also the lowest I have experienced.

I'd give up well before the watch. Guess it's be minus numbers °C on a motorbike. Wind chill. Too cold for me!!

Have you ever heard of this nifty invention called "car"? it has AC and heater inside I hear.

I take my Sinn EZM3 to hiking in the dead of winter. Had no problem at -25c.

Sinn says it is reliable down to -45c.

I’m more concerned with quartz as battery dies in extreme cold although my Garmin hasn’t died so far.

Also the sudden change in temperature from extreme cold to warm may be bad for watches as it causes condensation inside. EZM3 has dehumidifier so I haven’t had issues so far.

May not be a problem if you wear the watch directly on your skin under your clothes.

"Four wheels move the body two wheels move the soul " as they say ...

and two wheels without a helmet is a fast lane ticket to the heaven?

Unfortunately the nanny state in UK means a lid is compulsory 🤬

Even in cold temperatures, your watch will be kept at 37C/100F as it's close to your body and you are will be wearing a coat.

May not be a problem if you wear the watch directly on your skin under your clothes. -- @parechute

This is my thinking. For a normal person, the watch would be on a body-temperature wrist and covered by a coat sleeve and probably a glove. The risk of the wearer losing body heat becomes a problem first.

Now if we're going all adventure style, with watch exposed directly to the elements all day long, I'd have to be more choosy but I'd imagine that a majority of my modern watches would survive. Furthermore, I'd assume that any operation issues would be reversible. Cold would cause thermal contraction, and shrinking parts aren't likely to jam and distort moving parts as heating expansion is. As always, I may be wrong.

My Sinn U2 is designed to "Functions reliably at temperatures between -45 and +80 °C"

I got my first automatic in late winter/very early spring, and the coldest that I’ve worn it is -15°F, and it was running extremely fast, it kept getting exposed to the cold because it kept slipping out from under my coat sleeve

We’re just quirky and build different in the U.S

I guess watch boutiques shouldn't operate in many regions by this logic. Your watch will be fine unless you're racing dog sleds in Alaska for days at a time or something. Even then . . . just slip that watch under your fur skin coat. I live in Minnesota and have worn all of my watches to/from the car during -10, -20F blizzards. My watches are either in a travel pouch in an inside pocket if it's not on my wrist under my winter coat sleeve.

Well, I live in Alaska and go outside for hours on end in -30° temps, my watches just run fast by a few minutes in that kind of cold